1. Field of the Invention
This invention relates to apparatus and methods of coiling metal sheet and strip (hereinafter "strip"), in the form of one superlarge coil, for example as continuously cast and rolled from one entire metal heat, e.g. as produced in an electric furnace, including a special rig mounted under such coil for supporting the coil on spaced-apart driven rollers in a pattern conforming to the shape of the coil, and for transporting the coil.
2. Description of the Prior Art
Transportation of coils of metal strip by means of special coil handling equipment is known to the prior art, for example, U.S. Pat. No. 2,430,075 which shows a buggy, mounted on rails below normal floor level, and adapted for vertical movement, by means of an hydraulic cylinder, into engagement with a coil when the coil has reached a desired size and is to be moved.
Similarly, U.S. Pat. No. 2,734,405 provides coil loading and unloading carts mounted on rails to transfer a coil from storage to a rolling operation and to transfer the coil of rolled material to a desired destination.
U.S. Pat. No. 3,032,289 shows a coil conveyor including a vertically movable rail-mounted carriage for moving a coil into and out of an uncoiling position.
U.S. Pat. No. 4,152,919 provides long roller conveyors to transport coils to and from a rolling or processing operation and to storage.
U.S. Pat. No. 4,271,959 shows a coil handling device comprising a walking beam conveyor having V-shaped forks for receiving and supporting a coil to be transferred.
Supports for rolls of material, e.g. carpeting, are known, as in U.S. Pat. No. 2,834,558, to have a surface curved to conform to the roll surface and provided with rollers to facilitate unwinding of the carpet.
It also is known to the prior art to couple a continuous caster with a rolling operation, for example as shown in U.S. Pat. Nos. 4,698,897, 4,976,024 and 5,335,713. The latter patent provides two mandrels, mounted in a furnace between the caster and the rolling mill, and adapted for travel in a circular path for alternate winding and unwinding of the cast product.
Conventionally, strip rolling mills and processing lines produce coils with specific coil weights ranging from about 500 to about 1000 pounds per inch of coil width (about 9 to 18 kg/mm). In extreme cases, prior art coil specific weight may be as high as 1250 lb/inch (22.5 kg/mm). In hot strip mills that are designed to roll long, multiple-coil slabs, the rolled strip is divided by flying shears before entering a coiler.
If such a conventionally produced coil has to be further processed by using a continuous operation, for example, a pickling line, it is necessary to weld the ends of the separate coils together. The process of welding is expensive and, unless the quality of welding is strictly monitored, the welds can be broken during cold rolling. Frequently, the welding operation becomes a bottleneck that leads to decrease of production rate. The process of welding requires stopping the process line. Therefore, the line must include strip accumulators in order to process the strip continuously, thereby adding to the installation further substantial capital cost and operating and maintenance costs and difficulties.
In the case of hot strip mills designed to roll long, multiple-coil slabs, it is required to have a high speed (up to about 2000 ft/min or 10 m/sec) flying shear to divide the strip before it enters a coiler. This process requires a high-precision control, otherwise a strip cobble occurs.